The present invention relates to a substrate cleaning apparatus including a cleaning box, in which a substrate such as a semiconductor wafer is cleaned with a cleaning liquid and then dried, and also relates to a polishing apparatus equipped with such a substrate cleaning apparatus.
Typical in the prior art, a cleaning box of a substrate cleaning apparatus is provided with a substrate rotating mechanism located within the cleaning box. During a cleaning operation, a substrate is held in a horizontal plane by the rotating mechanism and rotated about its central axis, while a cleaning liquid, for example, a chemical cleaning liquid, is supplied to the surface of the substrate. In the conventional cleaning apparatus, to prevent a substrate cleaning liquid from diffusing outside the cleaning box during a cleaning operation, a closed-type cleaning box has been used; and during a cleaning operation, a negative pressure is applied to the inside of the box. When cleaning of the substrate is complete, it is preferably rotated at high speed to effect spin-drying. During a drying operation; however, there is a likelihood of liquid in mist form remaining in the closed-type cleaning box and being deposited on and contaminating a surface of the substrate being dried.
To avoid this problem, conventionally, a drying box has been provided separate from a cleaning box. The drawback of such an arrangement is that it results in an increase in size and cost of the cleaning apparatus.
The present invention has been made with a view to overcoming this problem, and provides a substrate cleaning apparatus by which a substrate can be cleaned and dried in a single dual-function box.
In accordance with the present invention, there is provided a substrate cleaning apparatus comprising a box in which a substrate is cleaned with a cleaning liquid, and an exhaust system for exhausting the box. The box is provided with an air intake opening for introducing air into the box to create an airflow passing around the substrate in the box and thereafter entering the exhaust system. The box is also provided with a door operable to close the air intake opening when an inside air pressure in the box becomes greater than an outside air pressure outside the box.
Specifically, the air intake opening is provided in the top wall of the box and the exhaust system is fluidly connected to the box at the bottom wall of the same to create an air flow flowing down in the box. The box is provided inside with a substrate rotating mechanism for rotating a substrate about its central axis, and at least one nozzle for supplying cleaning liquid to the substrate, while the substrate is rotated by the substrate rotating mechanism, to conduct a cleaning operation of the substrate. The substrate rotating mechanism is also operable to rotate the substrate at high speed after completion of the cleaning operation to dry the substrate.
In accordance with another aspect of the present invention, instead of provision of the door for closing the air intake opening, there is provided in the box at least one water nozzle for discharging water to form a water barrier across the air intake opening for preventing the cleaning liquid in mist or gas form from dispersing outside the box through the air intake opening. Specifically, there are provided two water nozzles which extend along either side edge of the air intake opening and discharge water in the form of a sheet in such a manner that the water discharged from the water nozzles cross each other to form the barrier. A plurality of baffle plates are provided over the air intake opening to form a plurality of air passages which allow air to freely pass therethrough, and also to check the water discharged from the water nozzle from scattering towards the outside of the box through the air intake opening. A control may be provided which operates the water nozzles to discharge water to form the barrier when an air pressure in the box is greater than an air pressure outside the box or when the exhaust system is broken down.
Further, the present invention provides a substrate polishing apparatus comprising a housing having a polishing chamber and a cleaning chamber. The polishing chamber is provided inside with a turntable having a polishing surface, and a substrate carrier for carrying a substrate to bring the substrate into contact with the polishing surface of the turntable for polishing the substrate, wherein the cleaning chamber is provided with at least one cleaning apparatus as stated above.